Jon is right: 'Anonymous' is an adjective, not a noun. If in some exceptional circumstances it is used as a noun, there is no problem with it following the rules used with every other unusual or proper noun, ie adding -es to make 'Anonymouses'.

While I agree that anonymous is an adjective, don't just dismiss the plural issue as a dumb question. I think it's quite an interesting one. Why, isn't the very example of "posted by anonymous" worthy of examination? One sees it all the time, but it really implies "posted by an anonymous author". Isn't it a strange construct? I might say, "I was passed by a blue car" but I would never say "I was passed by blue" even if the context was clear.As for "Look at all the anonymouses on this site" being incorrect, I have to disagree. I think Dave hit the nail on the head. Gee, at the very least, every word is a noun when you are treating it as a word and not its actual meaning.

As for the example "posted by anonymous", the implication is that the word 'anonymous' is a substitute for a name, and not functioning as a noun. It's almost like a box saying [insert name here]. Nevertheless, I agree it's not as dumb a question as it may sound. A sentence such as "look at all the anonymouses" sounds clunky but that doesn't make it invalid, so I have to agree.

But then what is a part of speech anyway. If I use an adjective as a noun, doesn't that make it a noun? I.e., not an adjective? Aren't greens, reds, and yellows nouns? Can they be both at the same time? Ok, I see your point. This doesn't matter because we are taking an utterance "anonymous" which normally behaves as an adjective, and treating it like a noun (making a noun from it). It's not an adjective being used as a noun (that doesn't make sense), it is simply, a noun. Ok, so then what's the problem? Just apply the usual English plural to it: anonymouses.

Lots of adjectives are often used as nouns. Regarding the issue at hand: the same adjective-as-noun can (1) sometimes add an "s" in the plural and (2) sometimes not. Take "great": (1) "That song is one of the all-time greats"(2) "The truly great don't need to advertise."Apologies for the not-great examples.

Now try sticking "anonymous" into the relevant positions:(1) That post is just one of the many anonymouses we receive.(2) The truly anonymous find advertising is no help.

For me, they both work. Even for the conservative (hidebound/uptight...), (2) is unexceptionable.

If there is a query about "anonymouses" it's surely in part because of the sound, which resembles that in "rhinoceroses", a correct plural that can nevertheless sound awkward.

If anyone can point out some generalisations about what adjectives can and what can't be used with plurals (assuming any such distinction is tenable), that would be an interesting post.

Can I be excused for being a 61 yr old whose English grammar has deteriorated from its peak when I graduated from high school? I just asked this question because I am writing a letter discussing "There Will Be Blood". I described the unknown workers, the grunts like me, as The Anonymous (e.g. The Anawim or The Proletariat.) I thought Anonymi would be cute. English is a bastard language anyway. That was a principle I did memorize from grade school

if Anonymous is being used as a name, then pluralise it like all other names:There are a lot of Bernards commenting on this post.There are a lot of Anonymouses commenting on this post.

it sounds weird because it ends with an s."There are a lot of Jameses commenting on this post" sounds weird too.

I think that where anonymous is not often found as a pluralised noun, nothing will sound quite right. Better to just keep it as an adjective and say "There are a lot of anonymous people" or alternatively say "There are a lot of people using the name "Anonymous""

now I need to look up whether I should be using 2 quotation marks in a row there.... hmmm

Generally I'd go with "anonymous people", "anonymous posters", "anonymous persons", and so on. If I was really intent on using a single word, probably specifically for the purpose of being silly or trying to emphasize informality, I'd go with "anonymouses".

On a side note, for M&Ms, I might actually say something like, "give me four green and five red," as a short form of, "give me four green ones, and five red ones." Then again, I often impose stricter grammar rules on myself than many people do, particularly on the internet. (And yes, I may have misused quotation marks here; I need to brush up on that)

The plural is anomymous (eg Alcoholics Anonymous).The plural of the word in the original greek would be something like anonym-οι or anonym-oi in the latin alphabet.The dipthong oi in greek is pronouced usually like "oi" in the "oil however in some case(this being one of them) is pronounced like "e"in "email".What I dont get is how the word ended up to be anonymous rather than anonymus since words like colossus have the same suffix in greek.

In 'Alcoholics Anonymous' it's still an adjective - meaning 'Anonymous alcoholics' - so that's a bit of a red herring. But I have to wonder when you would ever need a plural and if you did it would be likely to revert to being an adjective - The anonymous few / two - etc.

The problem with anonymities is it sounds to more like people nobody has ever heard of, rather than people who want to keep their anonymity:

"Amid the puny anonymities who inhabited what we have come to call the White House between Jackson and Lincoln" - David P.Currie

But there is a class of adjective we use for plural groups, and with a stretch of the imagination, anonymous might possible be used in a similar way -

"While the rich and famous lived on the hill, this side of town is mainly occupied by the poor and the unskilled, the homeless, the faceless and the anonymous."

In Britain we used to have a stereotype writer of angry letters to newspapers who was often referred to as ''Disgusted, of Tunbridge Wells" (perhaps there's an American equivalent). If he and his wife had signed jointly, would they have been "The Disgusteds"? I don't think the question has ever arisen.

I suppose the numerous posts over the years show that his question is not as silly as some seem to think.I personally came across this problem trying to formulate this sentence (GRE essay ...)"Thus, the heroes of today are no longer living individuals but dead anonymouses." (following a point about how the 9/11 firefighters are some of the last modern heroes because unlike with celebrities, there is no chance of tarnishing their reputation through media scrutiny)In this case, I think, it would be nice not to resort to "dead anonymous persons" in order to keep the living dead, individual anonymous.

Warsaw Will poses the question: ''Disgusted, of Tunbridge Wells". If he and his wife had signed jointly, would they have been "The Disgusteds"? I don't think they would ever have signed jointly for they would not be on speaking terms, being of a sour disposition, and would not collaborate on anything, let alone a letter. But if they were to do so, they would still be 'disgusted' just as the multiple people involved in the term 'the great unwashed' are not the great 'unwasheds'. As folk have been saying, above, for some years, it's an adjective, not susceptible to pluralising.

Ah, there's the rub. If it were "not susceptible to pluralizing" we would not be having this exchange. Mostly I follow the "rules". But as a fan of poets and writers who long have grasped the value of tweaking our language, I now feel confident in my decision to address my indignant letter to certain corporate anonymice.